Fastening devices for securing an externally threaded member such as a screw which utilize one or more resilient fingers or helically deformed edges surrounding an aperture through which the threaded member is inserted or combinations of both for engagement with the threads of the threaded member are well known in the art. Examples of fasteners utilizing free ends of resilient fingers or torques for engagement with the threads of a threaded member are disclosed in U.S. Pat. Nos. 2,239,797; 2,318,708; and 4,200,027, respectively. Examples of fastening devices which utilize a helically deformed edge of an aperture through which the threaded member is inserted are respectively disclosed in U.S. Pat. Nos. 2,228,584; 2,901,938; and 3,362,278. Examples of fasteners which use a combination of resilient fingers or tongues and a helically deformed edge of an aperture surrounding an opening through which the threaded member is inserted are respectively disclosed in U.S. Pat. Nos. 2,434,844; 2,494,882; and 3,308,708. The present invention concerns fasteners of the latter type particularly of the type disclosed in U.S. Pat. No. 3,308,708 involving the use of resilient fingers in combination with a helically warped edge of an aperture through which the threaded member is inserted for engagement of the free ends of the resilient fingers and the helically formed edge with the threads of the threaded member.
Although fasteners of the combination type described above, and in particular described in U.S. Pat. No. 3,308,708, may be used to advantage in providing a means of securing a threaded member, it has been found that such fasteners have a tendency to cock (i.e. tilt) the threaded member and cause undesirable cross-threading to occur. The problem has been found to be particularly prevalent when the leading end of the threaded member is flat rather than pointed (such threaded members in the form of screws are typically referred to as "blunt nosed" screws). In view of the above, a need exists to provide a fastener of the combination type described above that minimizes the tendency for cocking and cross-threading of the threaded member, particularly threaded members having flattened ends rather than pointed.